Postgres is not designed for OLAP, but you can push it a lot farther than one would expect with the correct schema and indexing strategy. See https://heap.io/blog/running-10-million-postgresql-indexes-i... for a little more detail about how we schematize for distributed OLAP queries on Postgres at scale.

They use Citus: https://www.citusdata.com/customers/heap

Who recently iterated on cstore_fdw to create columnar: https://www.citusdata.com/blog/2021/03/06/citus-10-columnar-...

But I don't think Heap's using columnar

We aren't using cstore_fdw, though we've looked into it in the past. cstore tables don't support deletes or updates, and we still rely on updates for some key parts of our write pipeline. Additionally, we rely heavily on btree partial indexes, while cstore tables only support skip indexes.